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Carnegie Mellon Co-Developing Helicopter Collision Avoidance System

By Dian Schaffhauser

07/12/10

Carnegie Mellon University's Robotics Institute is working with an aircraft company based in Essington, PA to create a navigation and sensor system that would enable a full-sized helicopter to fly at low altitudes while avoiding obstacles. The system developed and demonstrated by the Pittsburgh-based university and Piasecki Aircraft is designed to allow future unmanned helicopters to evacuate wounded soldiers from contaminated or live-fire battlefields and to resupply forward operating bases.

The technology is also applicable as an aid to help pilots avoid obstacles, such as power lines, and select landing sites in unimproved areas such as emergency scenes, even when operating in low-light or low-visibility conditions.

Participants in the project said that autonomous flight at low altitude and landing zone evaluation/selection is an unprecedented feat with a full-size helicopter. They tested the system at Boeing Co.'s Rotorcraft Systems facility in Mesa, AZ. In each test the software repeatedly demonstrated the ability to land in cluttered environments. The system also was able to detect and maneuver around a crane extended to a height of 60 feet while flying at a speed of more than 20 knots (about 23 miles per hour). Flight tests also demonstrated the sensor package was able to detect high-tension wires over desert terrain.

The sensor package includes inertial sensing and a laser scanner that can look forward or down, depending on flight parameters. Paired with mapping and obstacle avoidance software, these sensors build 3D maps of the ground and find obstacles in the aircraft's path. During the testing, the sensors demonstrated that they could detect four-inch-high pallets, chain link fences, vegetation, people, and other objects that could block a potential landing site. The laser scanner is effective even when dust obscures the landing site, as often occurs during operations in desert terrain.

The system is programmed to select a safe landing site that is closest to a given set of coordinates, such as the location of a casualty or a drop-off point for resupply. The software keeps a running rank of the possible landing sites and approach/abort paths, enabling the aircraft to respond rapidly to unexpected developments on the ground and in the air.

"Operation at low altitudes is where helicopters are most valuable, but also where they are most vulnerable," said Sanjiv Singh, research professor at the Robotics Institute. "Demonstrating that a full-scale robotic helicopter can safely take off, fly at low altitude, and land heralds a new era when we can significantly reduce risk, either by giving a pilot new aids for avoiding mishaps or by eliminating the pilot entirely."